A common type of wide agricultural implement includes right and left wing frame sections pivotally attached to a center frame section where the wing frame sections fold rearward for transport. Ground engaging tools such as discs, harrows and packers are mounted on the center and wing frame sections.
A hitch frame is mounted on center wheels at a rear end thereof and extends forward from the center wheels to a hitch tongue adapted to be attached to the drawbar of a towing vehicle. A center frame section is pivotally mounted on the rear end of the hitch frame about a hitch pivot axis that is perpendicular to the operating travel direction. Right and left elongate wing tool bars are in turn pivotally attached to outer ends of the center frame section about right and left wing pivot axes that are aligned with the operating travel direction when in the operating position so that the wing frame sections can pivot up and down with respect to the center frame section to follow ground contours. Wing operating wheels are attached to outer portions of each wing to support the wings in the operating position.
For transport the rear end of the center frame section is pivoted upward about the hitch pivot axis and the rear ends of the wing frame sections also pivot upward moving the ground engaging tools above the ground, and typically as the wing frame sections pivot upward, wing transport wheels move down into contact with the ground and the wing operating wheels are raised above the ground. The wing operating wheels are oriented to roll in the operating travel direction when the wings are in the operating position, and the wing transport wheels are oriented to roll perpendicular to the operating travel direction. Thus when the rear ends of the center and wing frame sections are raised to a position where the wing pivot axes is vertical, the operator can move the implement forward in the operating travel direction and as the center frame section moves in the operating travel direction, the wings frame sections move to a position trailing behind the center frame section and substantially aligned with the operating travel direction.
Such implements are disclosed for example in U.S. Pat. No. 4,821,809 to Summach, et al., U.S. Pat. No. 4,418,762 to Page, U.S. Pat. No. 3,640,345 to Sosalla, and U.S. Pat. No. 3,539,016 to Bauer et al. U.S. Pat. No. 2,828,597 to Moore shows a similar implement with a somewhat different arrangement where the frame is not pivoted, but the ground engaging tools, such as harrows which are relatively light, are simply moved manually to hang on racks. Here the same wheel is used for field and for transport and simply casters about its vertical axis.
U.S. Pat. No. 3,491,836 to Doepker discloses a similar winged implement where the center and wing frame section are moved to an upright position. The wing wheels are caster wheels pivotally mounted to the implement frame such that when the wings move to the upright position, the caster wheel remains on the ground. In this implement the wing frame sections are pushed forward riding on the castering wing wheels and secured to the hitch such that the wing frame sections ride on the castering wing wheels during transport.